Fred, Daphne, Velma, Shaggy, and Scooby-Doo go to Mexico to visit Fred's computer pen pal and to celebrate the Day of the Dead festivities, which become less festive when a towering, glowering Chupacabra monster turns up to terrify both tourists and locals. The young snoops smell a conspiracy, and as they chase down clues their search for the truth leads them into sundry Mexican antiquities - ancient tombs and temples - where danger increases exponentially.